Electrical control components



Sept. 12, 1961 D. G. MORRISH 2,999,992

ELECTRICAL CONTROL COMPONENTS Filed July 19, 1955 I 2,999,992 ELECTRICAL "CONTROL COMPONENTS Desmond George Morrish, Welling, England, assiguorto Ardente Acoustic Laboratories Limited, London, England, a British company Filed July 19, 1955, Ser. No. 523,069 Claims priority, application Great Britain July 19, 1954 4 Claims. (Cl. 338-163) This invention-relates to electrical control components and is applicable to manually operable variable resistances used as volume controls .or the like, and manually operable switches. 9

According to the present invention there is provided an electrical control component comprising twodisc-like plates held in spaced co-axial relation, an annular control which:

FIGURE 1 is a cross-section of avariable resistance component and,

FIGURE 2 is an underneath plan view of the component shown in FIGURE 1.

Referring now to the drawings, a disc-like plate 1 has a C-shaped resistance element 2 located on its surface, the G-shaped resistance being centred about the axis of the plate 1 and being located remotely from the centre of the plate. The resistance element 2 is held in position by two studs 3 and 4 which are positioned at the ends thereof. The studs extend beyond the surfaces of the element 2 and the plate 1. A manual control head 5, formed as an annulus coaxial with the plate 1, has a shoulder 6 which bears against the periphery of the plate 1. The control head has an inwardly extending flange 7, which at 8 is further inwardly extended and formed with an aperture 9 in which a contact member 10 is located, the contact member being free to move in a direction normal to the plate 1. An annular spring leaf 11 bears on the contact member 10 to urge it towards the resistance element 2, the spring being held in position by a shoulder 12 formed on a central spacing bush 13 and by the flange 7. The upper end surface of the spacing bush 13 abuts a second disc-like plate 14, of similar shape to the plate 1, and which likewise at its periphery bears against a shoulder 15 formed on the control head 5. The control head 5, and the plates 1 and 14 are all retained in fixed spaced relation by an eyelet 16 passing through the spacing bush 13.

In the component just described, the plates 1 and 14 and the control head are made of insulating material, but the spring 11, the spacing bush 13, the studs 3 and 14 and the eyelet 16 are made of a conducting material.

The control head is free to rotate about the axis of the component, and the bearing of the control head is effectively formed by co-operation of the shoulders 6 and 15 with the plates 1 and 14, the bearing surfaces being remote from the axis of rotation.

The control head 5 can be dimensioned to suit the particular location in which the assembly is to be utilised. For example, the peripheral thickness of the control head may be made less than the distance between the outside surfaces of the plates 1 and 14, whereby the component may be fitted tightly into a slot whilst the control head remains free from the edges of the slot.

United States Patent 0 action of the spring 11. An electric conducting path exists through one or both studs 3 and 4, the resistance element 2, contact element 10, the spring 11, the shoulder 12, the eyelet 16 and the locating screw. It will be realised that the resistance of the component will be varied in dependence on the position of the contact element 10.

The rotation of the control head 5 can be restricted by one or both of the studs 3 and 4 acting as end stops. It is to be noted that the variable resistance can be .connected in such a way that it forms a rheostat or a potentiometer.

The inwardly extended part 8 of the flange 7 may be adapted to operate a switch mechanism mounted in the centre part of the component. In this way an on-off switch can be incorporated to come into action at one end of the resistance element 2. Furthermore, if so desired, the element 2 may be replaced by a conductor having discontinuities or separate contacts so that the component acts simply as a switch.

The component design reduces the possibility of dust entering the interior and can be made in miniature so that it is particularly useful as a finger-tip volume control for deaf-aids.

I claim:

1. An electrical control component comprising two similar disc-like plates located in spaced and co-axial relation, an annular control head co-axial with the plates and manually rotatable with respect thereto about its axis and forming with said plates a housing in the general shape of a short cylinder or disc, annular bearing surfaces on said control head co-axial therewith and in engagement with corresponding surfaces at the peripheries of the plates to form bearings for the rotational movement and at the same time to locate said control head on the plates and space the latter apart, a centrally located spacing member to further assist in spacing said plates apart, fastening means extending between the two plates to press them against said spacing member and against the bearing surfaces of the control head, a resistance element mounted on the inward face of one of said disc-like plates, an inwardly extending projection on said control head, a contact member located in, and by, said projection for contacting said resistance element and for traversing the latter, terminal means on at least one of said plates for connection to an external circuit, and connecting means connecting said element and said contact member to said terminal means, whereby rotation of said control head causes variations of resistance in said external circuit.

2. A component according to claim 1, in which said resistance element has at least one discontinuity therein, whereby rotation of said control head causes switching functions to be performed.

3. An electrical control component comprising two similar disc-like plates located in spaced and co-axial relation, an annular control head co-axial with the plates and manually rotatable with respect thereto about its axis and forming with said plates a housing in the general shape of a short cylinder or disc, annular bearing surfaces on said control head co-axial therewith and in engagement with corresponding surfaces at the peripheries of the plates to form bearings for the rotational movethe plates and space the latter apart, a centrally located spacing member to further assist in spacing said plates apart, fastening means extending between the two plates to press them against said spacing member and against the bearing surfaces of the control head, a conducting element mounted on the inward face of one of said plates and having discontinuities therein, an inwardly extending projection on said control head, a contact member located in, and by, said projection for'contacting said conducting element and for traversing the latter, terminal means on at least one of said plates for connection to an external circuit, and connecting means connecting said contact member and said conducting element to said terminal means, whereby rotation of said control head causes switching functionsto be performed.

4. An electrical control component comprising two similar disc-like plates located in spaced and co-axial relation, an annular control head co-axial with the plates and manually rotatable with respect thereto about its axis and forming with said plates a housing in the general shape of a short cylinder or disc, annular bearing surfaces on said control head co-axial therewith and in engage ment with corresponding surfaces at the peripheries of the plates to form bearings for the rotational movement and at the same time to locate said control head on the plates and space the latter apart, a centrally located spacing member to further assist in spacing said plates apart,

fastening means extending between the two plates to press them against said spacing member and against the bearing surfaces of the control head, a C-shaped resistance element mounted on the inward face of one of said plates, two studs located at the ends. of said element and passing through said one plate to constitute a pair of terminals, an inwardly extending pr jection on said control head, a. contact member located in, and by, said projection for contacting said resistance element and for traversing the latter, and asubstantially annular electrically conducting leaf spring bearing on said contact member for urging the latter against said resistance element, sm'd fastening means extending between the two plates comprising an electrically conducting. eyelet in electrical contact with said leaf spring and passing through the axis of said plates to hold the latter in co-axial relation and to constitute a terminal.

References Cited in the file of this patent UNITED STATES PATENTS 2,329,949 Shapiro Sept. 21, 1943 2,415,858 Youhouse Feb. 18, 1947 2,451,241 Rosentreter Oct. 12, 1948 FOREIGN PATENTS 210,944 Great Britain Feb. 14, 1924 105,970 Austria Nov. 15, 1926 

